1 /*
2 * Copyright (c) 2000, 2022, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 package sun.jvm.hotspot.oops;
26
27 import java.io.*;
28 import sun.jvm.hotspot.debugger.*;
29 import sun.jvm.hotspot.runtime.*;
30 import sun.jvm.hotspot.types.*;
31 import sun.jvm.hotspot.utilities.Observable;
32 import sun.jvm.hotspot.utilities.Observer;
33
34 // Oop represents the superclass for all types of
35 // objects in the HotSpot object heap.
36
37 public class Oop {
38 static {
39 VM.registerVMInitializedObserver(new Observer() {
40 public void update(Observable o, Object data) {
41 initialize(VM.getVM().getTypeDataBase());
42 }
43 });
44 }
45
46 private static synchronized void initialize(TypeDataBase db) throws WrongTypeException {
47 Type type = db.lookupType("oopDesc");
48 mark = new CIntField(type.getCIntegerField("_mark"), 0);
49 klass = new MetadataField(type.getAddressField("_metadata._klass"), 0);
50 compressedKlass = new NarrowKlassField(type.getAddressField("_metadata._compressed_klass"), 0);
51 headerSize = type.getSize();
52 }
53
54 private OopHandle handle;
55 private ObjectHeap heap;
56
57 Oop(OopHandle handle, ObjectHeap heap) {
58 this.handle = handle;
59 this.heap = heap;
60 }
61
62 ObjectHeap getHeap() { return heap; }
63
64 /** Should not be used or needed by most clients outside this
65 package; is needed, however, by {@link
66 sun.jvm.hotspot.utilities.MarkBits}. */
67 public OopHandle getHandle() { return handle; }
68
69 private static long headerSize;
70 public static long getHeaderSize() { return headerSize; } // Header size in bytes.
71
72 private static CIntField mark;
73 private static MetadataField klass;
74 private static NarrowKlassField compressedKlass;
75
76 // Accessors for declared fields
77 public Mark getMark() { return new Mark(getHandle()); }
78 public Klass getKlass() {
79 if (VM.getVM().isCompressedKlassPointersEnabled()) {
80 return (Klass)compressedKlass.getValue(getHandle());
81 } else {
82 return (Klass)klass.getValue(getHandle());
83 }
84 }
85
86 public boolean isA(Klass k) {
87 return getKlass().isSubtypeOf(k);
88 }
89
90 // Returns the byte size of this object
91 public long getObjectSize() {
92 Klass k = getKlass();
93 // All other types should be overriding getObjectSize directly
94 return ((InstanceKlass)k).getObjectSize(this);
95 }
96
97 // Type test operations
98 public boolean isInstance() { return false; }
99 public boolean isInstanceRef() { return false; }
100 public boolean isArray() { return false; }
101 public boolean isObjArray() { return false; }
102 public boolean isTypeArray() { return false; }
103 public boolean isThread() { return false; }
104
105 // Align the object size.
106 public static long alignObjectSize(long size) {
107 return VM.getVM().alignUp(size, VM.getVM().getMinObjAlignmentInBytes());
108 }
109
110 // All vm's align longs, so pad out certain offsets.
111 public static long alignObjectOffset(long offset) {
112 return VM.getVM().alignUp(offset, VM.getVM().getBytesPerLong());
113 }
114
115 public boolean equals(Object obj) {
116 if (obj instanceof Oop other) {
117 return getHandle().equals(other.getHandle());
118 }
119 return false;
120 }
121
122 public int hashCode() { return getHandle().hashCode(); }
123
124 /** Identity hash in the target VM */
125 public long identityHash() {
126 Mark mark = getMark();
127 if (mark.isUnlocked() && (!mark.hasNoHash())) {
128 return (int) mark.hash();
129 } else if (mark.isMarked()) {
130 return (int) mark.hash();
131 } else {
132 return slowIdentityHash();
133 }
134 }
135
136 public long slowIdentityHash() {
137 return VM.getVM().getObjectSynchronizer().identityHashValueFor(this);
138 }
139
140 public void iterate(OopVisitor visitor, boolean doVMFields) {
141 visitor.setObj(this);
142 visitor.prologue();
143 iterateFields(visitor, doVMFields);
144 visitor.epilogue();
145 }
146
147 void iterateFields(OopVisitor visitor, boolean doVMFields) {
148 if (doVMFields) {
149 visitor.doCInt(mark, true);
150 if (VM.getVM().isCompressedKlassPointersEnabled()) {
151 visitor.doMetadata(compressedKlass, true);
152 } else {
153 visitor.doMetadata(klass, true);
154 }
155 }
156 }
157
158 public void print() { printOn(System.out); }
159 public void printValue() { printValueOn(System.out); }
160 public void printRaw() { printRawOn(System.out); }
161
162 public static void printOopValueOn(Oop obj, PrintStream tty) {
163 if (obj == null) {
164 tty.print("null");
165 } else {
166 obj.printValueOn(tty);
167 tty.print(" @ " + VM.getVM().getUniverse().heap().oopAddressDescription(obj.getHandle()));
168 }
169 }
170
171 public static void printOopAddressOn(Oop obj, PrintStream tty) {
172 if (obj == null) {
173 tty.print("null");
174 } else {
175 tty.print(obj.getHandle().toString());
176 }
177 }
178
179 public void printOn(PrintStream tty) {
180 OopPrinter printer = new OopPrinter(tty);
181 iterate(printer, true);
182 }
183
184 public void printValueOn(PrintStream tty) {
185 try {
186 tty.print("Oop for " + getKlass().getName().asString());
187 } catch (java.lang.NullPointerException e) {
188 tty.print("Oop");
189 }
190 }
191
192 public void printRawOn(PrintStream tty) {
193 tty.print("Dumping raw memory for ");
194 printValueOn(tty);
195 tty.println();
196 long size = getObjectSize() * 4;
197 for (long i = 0; i < size; i += 4) {
198 long memVal = getHandle().getCIntegerAt(i, 4, true);
199 tty.println(Long.toHexString(memVal));
200 }
201 }
202
203 public boolean verify() { return true;}
204
205 public static Klass getKlassForOopHandle(OopHandle handle) {
206 if (handle == null) {
207 return null;
208 }
209 if (VM.getVM().isCompressedKlassPointersEnabled()) {
210 return (Klass)Metadata.instantiateWrapperFor(handle.getCompKlassAddressAt(compressedKlass.getOffset()));
211 } else {
212 return (Klass)Metadata.instantiateWrapperFor(handle.getAddressAt(klass.getOffset()));
213 }
214 }
215 };